Although environmental cleaning and disinfecting practices have become a cornerstone of patient care, assessment of actual compliance with such procedures has not been reported. During the past decade controlling and limiting the spread of health care associated pathogens has become one of the most challenging aspects of health care epidemiology. Unfortunately the continuing escalation of infections with these pathogens has led to more than 1.5 million people developing resistant hospital acquired, i.e., nosocomial, infections in the U.S. annually. Despite enhancement of hand hygiene through the development of user friendly alcohol based hand cleansers, the manner in which they are used and the difficulty achieving appropriate compliance with their use potentially limit their effectiveness.
Three pathogens posing significant nosocomial problems are MRSA (Methicillin Resistant Staphylococcus aureus), VRE (Vancomycin Resistant Enterococcus), and Clostridium difficile (C. difficile). Their importance derives from a combination of resistance to presently available treatments and an ability to rapidly spread extensively in the environment around hospitalized patients. MRSA is present in wound infections, as associated with bed sores and catheters. VRE is present in bowel and urinary tract infections. C. difficile is also present in bowel infections and presents as severe diarrhea. For each of these pathogens, control with present antibiotics is problematical, if not impossible.
Although screening based isolation practices have been advocated to limit the transmission of MRSA and VRE, there are logistical issues and concerns about the practical application and cost effectiveness of such practices. Reliance on such practices may alter the epidemiology but not the incidence of health care associated infections. Additionally, outbreak persistence as well as significant environmental contamination occurs despite patients being on isolation for VRE and MRSA as well as for patients who are asymptomatically colonized with C. difficile for which screening is not feasible. These programmatic as well as pathogen based issues clearly have limited the effectiveness of current as well as proposed isolation practices.
Enhancement of existing cleaning and disinfection practices deserves further consideration and evaluation. Although it is not currently feasible to define the independent role of the hospital environment in the transmission of health care associated pathogens except in isolated investigations, numerous studies over the past twenty years have confirmed the frequent contamination of many surfaces in the near patient environment with hospital associated pathogens able to survive on inanimate surfaces for weeks to months.
With respect to individual pathogens, it has been found that high rates of environmental contamination with C. difficile have been associated both with symptomatic as well as asymptomatic patients. Direct evaluation of the role of environmental contamination in the transmission of C. difficile found a strong correlation with the intensity of environmental contamination, and outbreaks of C. difficile infection have been successfully terminated by enhanced cleaning/disinfecting activities.
The role of environmental contamination in transmission of VRE has been documented. Recent studies have confirmed the frequency of environmental contamination, shown to be highly correlated with the number of body sites colonized as well as with the intensity of gastrointestinal tract colonization. Furthermore the ease with which gloved hands can become contaminated by limited contact with a colonized patient's bed rail and bedside table the rapid recontamination of surfaces in the near patient environment with VRE despite effective daily cleaning even in the absence of diarrhea as well as the termination of a VRE outbreak in an ICU through enhanced cleaning activities support the likely importance of the environment in the epidemiology of VRE.
MRSA is frequently found in the environment of both colonized and infected patients and colonized health care workers. The pathogen can be transmitted by the gloves of health care providers and increases in concentration in the stool of colonized patients receiving broad spectrum antibiotics. Consequently, it is likely that environmental contamination plays a role in the spread of MRSA. In addition, DNA typing in three studies has supported the likely importance of environmental reservoirs in colonal MRSA outbreaks in hospitals lasting from three months to five years.
These and similar observations confirm the longstanding belief that environmental cleaning/disinfecting activities are important in providing an optimally safe environment for patients and have led to the development of specific guidelines for environmental infection control in health care facilities. The Center for Disease Control, for example, has recommended that hospitals “thoroughly clean and disinfect environmental medical equipment surfaces on a regular basis”. Similarly, the Society for Health Care Epidemiology of America's position paper regarding enhanced interventions to control the spread of resistant Staphylococcus aureus and Enterococcus recommended that hospitals “ensure” that their institutional methods of disinfecting surfaces be shown to be “adequate”.
Finally, the Joint Commission for Health Care Accreditation states “hospitals are expected to develop standards to measure staff and hospital performance in managing and improving the environment of care” without defining what specific resources should be utilized to carry out such activities.
In view of the above, there is a need for a non-microbiological methodology to evaluate the thoroughness with which housekeeping activities are carried out in hospitals, food service applications, and other industrial, institutional and commercial cleaning of surfaces.